Table 1. Prevalence of key genetic alterations in biliary tract cancers.

Variables	IHCC (%)	EHCC (%)	GBC (%)	References
Tyrosine kinase signaling
EGFR	4	3	4–18	(16,17)
HER2	1.5–3	11–18	10–16	(16,18-20)
KRAS	17–30	12–40	0–13	(16,17,19-21)
BRAF	4–7	3	1–6	(16,19,22,23)
PIK3CA	5–6	7–9	8–14	(19,21,24,25)
FGFR2 fusions	6–50	0–5	0–3	(17,19,26-29)
IDH pathway	10–28	0–7	0	(19,21,27,30-32)
Chromatin-remodeling genes
ARID1A	17	12	13	(19,27)
BAP1	11	8	0	(17,27)
PBRM1	8	5	7	(17,27)